Hearing aid construction



Dec. 7, 1954 A, WATSON 2,696,527

HEARING AID CONSTRUC'T:EON

Filed April 21, 1950 United States Patent C HEARING AID CONSTRUCTION Leland A. Watson, Minneapolis, Minn., assignor to The Maico Company, Incorporated, Minneapolis, Minn., a corporation of Minnesota Application April 21, 1950, Serial No. 157,230

2 Claims. (Cl. 179-107) In hearing aids of the type above-described, it has been l common practice to secure t-he microphone to the front walls of the casing behind and in I'alignment with a microphone or sound aperture in said front walls. This construction is objectionable for two reasons. In the first place, the microphone, being immediately behind the front wall of the casing, must necessarily rub against the clothing of the wearer when it is placed in the wearers pocket. This rubbing contact creates frictional electricity which is picked up by the microphone and, as a result, objectionable rasping noises are too frequently passed on to the ear of the user. Secondly, because the sound aperture is located in the front wall of the casing, the sound picked up by the microphone must necessarily pass through the clothing of the wearer. Clothing, irrespective of its thickness, has some dampening effect upon the sound signals picked up by the microphone.

The primary object of my invention is the provision of a device of the class described, which will reduce to -a minimum the amount of clothing noise picked up bv the microphone thereof when placed in the pocket of the wearer.

A still further and highly important object of my invention is the provision of a device which, when placed in a pocket of the wearer, will piek up a maximum extent of the desired signal.

The above and still further objects of my invention will become apparent from the following detailed speciiication, appended claims, and Iattached drawings.

Referring to the drawings, wherein like characters indicate like parts throughout the several views:

Fig. 1 is a top plan view of my novel hearing aid;

Fig. 2 is a side plan view of my novel device, some parts being broken away; and

IFig. 3 is a view, partly in side plan and partly in vertical axial section, as taken from the line 3-3 of Fig. 2.

Referring with greater particularity to the drawings, the numeral 1 indicates, .in its entirety, `the casing of an electronic hearing aid including a front wall 2, rear wall 3, side walls 4 and 5, a bottom end wall 6, and a Itop end wall 7. I-t will be seen that the top end wall 7 is provided with a sound laperture 8, preferably covered with a perforate grill 9 interposed between the under surface of the wall 7, and a rubber cup-like casing 10 sur rounding the microphone 11. As shown, the microphone 11 and rubber cup-like casing 10 rest upon a shelf 12 within lthe casing between upstanding partitions which limit lateral movement of the microphone 11.

The microphone, through lead 14, is coupled to the input of an electronic amplier including tubes 15 within the casing. A switch and volume control knob 16 is secured within the casing by means of a set screw 17, which has its peripheral edge 18 projecting outwardly through an opening 19 in the side wall 4. The electronic amplilier is conventional in nature and, inasmuch as the "ice same does not comprise the essential part of the invenltion, 1it is not thought necessary to describe the same in etai With respect to the sound aperture 8, `it will be observed that the same is spaced inwardly from the side walls 4 and 5 and front and rear walls 2 and 3. This arrangement makes it possible to insert the casing 1 into a pocket of the user without the sound aperture 8 being in con-tact with any of the wearers clothing, thereby eliminating or reducing to a minimum the amount of clothing noise picked up by the microphone 11. Furthermore, when my novel structure is placed in a relatively shallow pocket, such as yin the vest pocket of the wearer, the upper end of the casing 1 keeps the upper end of the pocket open. Under such circumstances, it is not necessary for the sound Waves to pass through the clothing of the wearer before entering the sound aperture 8. The sound waves may pass directly 'to the sound aperture 8 through -the open end of the pocket. In this manner, a maximum signal is picked up by the microphone 11.

My invention has been thoroughly tested and found to be completely satisfactory for the accomplishment of the above objects; and the drawings illustrate the commercial embodiment of same.

What I claim is:

1. In a hearing aid of the type carried in a clothing pocket, a casing defining front, back, side and end walls, the upper end wall being rectangular and having an upwardly directed sound receiving aperture therein, a microphone mounted within said casing and having its diaphragm disposed immediately below land closely and directly adjacent said sound aperture for direct passage of sound in a straight line from said aperture into said microphone, -an electronic amplifier in said casing, said microphone being coupled to the input of the amplifier, said aperture being disposed centrally of said upper end wall and having the edges of said aperture each spaced from the edges of -the upper end wall to thereby increase 'to maximum the path of travel of clothing noises from the walls of the casing to the sound aperture, said casing having parallel partition ribs depending from said upper end wall vand on opposite sides of said sound aperture, said partition ribs engaging opposite sides of said microphone for ixedly positioning vthe latter relative to the sound aperture.

2. In -a hearing aid of the clothing pocket carried type, a casing dei-ined by front, back, side and upper .and lower end walls, the upper end Wall being of rectangular form and having an upwardly directed sound receiving aperture therein, a microphone mounted within said casing yand having its diaphragm disposed below and closely adjacent said sound receiving aperture and in right angular relation Ito the axis of s-aid aperture for direct passage of sound waves through said aperture and into said microphone, an electronic amplifier yin said casing, said microphone being coupled to the input of the amplifier said aperture being disposed centrally of said upper end wall and having the edges thereof each spaced from the corresponding edges of the upper end wall providing a continuous relatively wide clothing spacing area surrounding said aperture.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,199,555 Andrews Oct. 27, 1932 2,327,320 Shapiro Aug. 17, 1943 2,351,400 Carlise June 6, 1944 2,419,471 Thibos Apr. 22, 1947 2,495,476 Posen Jan. 24, 1950 2,524,393 Lybarger Oct. 3, 1950 2,533,516 Schwalm Dec. 12, 1950 

